On a recent trip to a watch store in Seth Casteel’s hometown of Los Angeles, a salesperson started making small talk by asking him what he did for a living.

“I’m a photographer,” Casteel said.

“Oh, have you seen those underwater dog photos that are going around?” she responded immediately.

“Yeah, I shot those,” Casteel said.

“No way! I can’t believe you’re in the store right now,” the clerk shouted.

Similar scenes have played out a handful of times in the past few weeks for Casteel, whose unique underwater dog photos went viral earlier last month and became a global phenomenon.

“It’s been pretty unreal,” Casteel says.

Before the photos spread across the world, Casteel was doing okay as a freelance photographer. He sometimes struggled to pay the bills, but his list of clients was growing. He was actually on a shoot for Animal Planet when the photos first started to get around.

Now everything has changed. On that fateful February 9th, the photos mysteriously landed on Reddit, Facebook, Google+ and then Warholian, becoming one of the hottest trends amongst viewers on at least five or six continents.

More than 1,000 people all over the world have subsequently asked him to shoot photos of their pets. He’s got a line of publishing houses fighting to get the rights to his forthcoming book of underwater dog photos, and he’s made appearance on, or in, most major American news publications from the The New York Times to Good Morning America.

“I could have never predicted anything like this,” says Casteel, who seems to have remained humble in the face of his newfound fame.

While many viral stars have floundered under the attention, Casteel says he was actually well positioned to deal with the onslaught. His website crashed a couple times because of the hundreds of thousands of hits he continues to receive, but that seems to have been the only hiccup.

He credits his licensing and PR firm, Tandem Stills + Motion, with successfully converting his new audience. Where many internet stars fade away after a few days of intense popularity, his firm capitalized on the traffic by handling most of Casteel’s business transactions and press requests.

“The business side is so important because you can have something go viral and be silly about it and you won’t make a dollar off it,” Casteel says. “Without [Tandem Stills + Motion] it would have been a fail.”

The company’s smaller size and client focus was also instrumental. “If I would have been with Getty or Corbis it would have been a mess,” he says.

The only detail Casteel will reveal about his new financial situation is that he has gone from “a struggling entrepreneur to someone who is going to have a career.”

He raised his prices, but only slightly. His on-land photos shoots went from $375 to $450 for an hour. An underwater shoot, which takes several hours, now starts at $995.

“I want to be accessible,” says.

The only things Casteel has thought about splurging on are an additional underwater housing for his Canon 7D and some new dog tattoos. He’s currently working on an entire sleeve of dog portraits but hasn’t found much time to get new ink because he’s constantly in a pool.

The most exciting part of the success for him, however, is how the attention has already helped his non-profit, Second Chance Photos, which aims to increase the quality of animal adoption photos at shelters across the country by providing photo equipment and technical training for shelter staff. Better photos, Casteel says, means increased adoption rates.

He got involved in helping animals after some kittens wandered onto a movie set he was working on and he agreed to do their adoption photos. From there he moved on to volunteering at the West Los Angeles animal shelter and then started Second Chance.

Now Casteel’s recent success has lead to an increase in donations to the non-profit. It’s also led to invitations from animal shelters outside the U.S. who are interested in the workshops.

“That’s the thing I’m most surprised about,” he says. “That the photos have resonated with so many people across the world. In the end I’m just super grateful and excited that it’s been such a positive thing.”